A code division multiple access (CDMA) receiver may comprise a rake receiver, which may include multiple receiving elements, called fingers, which de-spread a received signal. A finger may be synchronized to a path of a multi-path channel between a base station and a mobile receiver. Information, such as symbols bounded by symbol boundaries, may be transferred from the fingers to a processor.
However, the timing of one finger may change independently of another finger, due to such factors as a dynamic environment and movement of the mobile station, for example. The lack of synchronization of the fingers may make it difficult for the processor to recognize the symbol boundaries for a particular finger.
In one possible solution, a finger may generate “interrupts” at a rate synchronized to the symbol boundary rate of the finger. The processor may read and process a fixed number of symbols between successive interrupts. For example, if the interrupt rate were equal to the symbol rate, then the number of symbols bounded by successive interrupts would be equal to the number of symbols bounded by successive symbol boundaries.
A disadvantage of the abovementioned interrupt method may be that a very large processing and memory overhead may be required to process a large number of fingers.
It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.